Telephone-exchange system.



R. H. MANSON. TELEPHONE EXCHANGE SYSTEM; 4 APPLICATION FILED MAY 22, 1906.

1,038,61 Z, Patented Sept. 17, 1912.

2 SHEETS-SHEET 1.

wammw R. H. MANSON.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED HAY 22,1906. 5 1 Patented Sept. 17, 1912.

2 BEEE'TB-BHEET'a.

RAY n. MANSON, or

nLYnm, on-massronon TO THE DEAN ELECTRIC COMPANY, orv

ELYRIA, care, A- conronarron on cam.

TELEPHONE-EXCHANGE SYSTEM.

eeann.

To all whom it may concern Be it known that I, RAY H. MANSON, a'

' originated.

In handling trunk callsfthe best practice at present gives the supervision of all conncctions to the A operator, that is the subscribers operator who originally answers the call and initiates the desired connection.

The actual ringing, however, is not always possible to be done directly by this A operator, for the reason'th-at many trunks have complicated arrangements of relays, etc, and in addition have a resistance which taken with that of the line called and considering losses from intermediate bridges and the like, would very perceptibly diminish the elfect finally produced at the called sta tion. The ringing is therefore usually done.

by the B or trunk operator,v as directed by the A operator. here selective ringing is practised, in partyline'callsrthe B operator also sets up the proper isclective It is my purpose "in the present case to give the i operator absolute control of the ringing.- A circuit of this type, however, must fulfil the following conditions.

First-The trunk must terminate in mul tiple jacks at the A board and in plugs and supervisory lamps at the B board of the distant ofiice.

Second-The B i end of the trunk must have a normal connectionfrom the tip of the plug to theoperatoris busy test. This connection must be controlled by a relay so that the insertion of theaplug will automatically disconnect the'test circuitand con net-t the talking circuit through to the A switchboard. y

'lhird- 'lhe disconnect lamp at the B board must be controlled by theinscrtion Specification of Letters Patent. Application filed May 22, 1906. Serial No. 318,250.

Patented Sept.1"7, 1912.

and removal of a-pliig at the A board. If the A operator-inserts the plug before the B operator makes the desired connection, the disconnect lamp will light; in other words, serving as a guard.

Fourth-The ringing lamp must be located at the B position in conjunction with each one of these trunks, which will light on inserting the plug at the B board and extinguish when the subscriber responds, and then stay locked out until the connection is pulled down. \Vhen automatic ringing is provided this ringing lamp is not essential, but can be used as a guard if desired.

Fifth The supervisory lamp in the A switchboard cord-circuit which is connected to one of these trunks, must be controlled by the distant subscriber connected tothe B end of the some trunk: thus, the disconnect signal is first received by the A. operator, and when she pulls down her connecting cord the disconnect lamp located at .the B end'of the trunk, will light.

Sixth- 1 he current for supplying the subscribersinstrument must be furnished from the B end of the trunk and come from the B exchange storage battery.

Seventh-The B operator must do all the ringing. either individual or party-line ringing, and she will not be able to throw generator current out to line until the A- operator inserts a plug into the other end of the trunk used- Hy present system is designed to meet these conditions. and briefly stated it operates as follows: In initiating the connection, the A operator gets on the order wire to the B otlicc, and orders up a trunk in the usual manner, the B operator responding by designating the trunk to be used, and

, proceeding at once to test the jack of the line wanted. The A operator plugs in on the trunk designated, thereby energizing certain relays at the B end, which connect the ringing circuit and light a guard lamp. Then the B operator finally plugs in on I the wanted subscribers lino she extin'guishes the guard lamp and lights a ringing lamp. She then rings in the usual way. and

when the subscriber answers the. ringing -lainp is cut out and the controlling relay therefor is locked so the lamp will remain extinguished. .\t the same tune sulhcicnt current is permitted to pass through the trunk to operate the supervisory relay at the A operators position and show her that the call is answered. When-the opera-' tor pulls down,- her connection battery is disconnected from the A end of the trunk, and a disconnect lampis lighted before the B operator, who pulls down her part of the connection. The gist of the present invention lies in the control of the B ring ing circuit by the A operator.

My invention is illustrated in the accompa pving drawings, in which gure 1 is a diagram showing a trunkline'extending between two city exchange offices, with a portion of the A operators cord-circuit at the first othce, and a subscribers line at the second ofiice. Fig. 2 is a diagram of a modification of Fig. 1.

Referring to the drawings, and particularly to Fig. 1, J represents the terminal jack of an outgoing trunk from one city ofiice to another, or it may be the terminal of a trunk between divisions of the same 'ofiice. At the other end this trunk termimates in a plug P. The jack J is at what is called the A end of the trunk, and the plug P at the. B end. Two diflerent classes of operators are employed at each. exchange, A operators and B operators' The first are also called subscribers .operators, and the second trunk operators. The main portion of the trunk-line extending between these operators is shown at 1-2,

and the continuity of the trunk for direct currents is broken at the-B ofiice where the repeating coil I and the condensers C The trunk jack J, has

are interposed. spring-contacts and a so-called thimble or test contact, butin'my presentdiagrams a two-wire circuit is shown, so the long spring and the test contact are tied together an to groundthrough Wire 3 and the choke- -coil 4. Cooperating with the jack J is an operators plug P, whose tip' and sleeve contacts form the terminals'of cord-conductors 5-6, whichgtre supposed to be matched with other cord-conductors leading to the answering plug with which the operator may re 'spond to calling subscribers. This answering plug and its "conductors are not shown, since they form no part of the present invention. Thev cdnductors 56 have bridged across them the main battery-B and a sleeve and a tip relay R and R, respectively, which control the battery supply to the supervisory lamp L. On the right-hand side of Fig. 1 I have shown a subscribers line having a. central oihce terminal or' sprin -jack J with three contacts like the iack a cut-off relay N, a line-relay M, a inc-signal lamp m, line-wires 7 and 8, a substation set comprising a transmitter '1, receiver T, ringer Q, switch-hook H, condenser C and at the central office a normal connection from wire 7 to ground and from line-circuit shown are of standard type, and

their mode of operation is well understood and obvious from the diagrams. When a plug such as P is inserted in a jack, such as J, current will flow from the battery B through the cord-relay R and conductor 6 to the relay N and ground. This relay then pulls up its armature, cuttin ofl" the linesignal relay; and the relay .pulls up its armature putting battery on the lamp L if the relay R is at the same time deenergized. If the line is calling, so that the subscribers receiver is oil the hook, relay R will also deprived of current; but if the line is being called, the relay R will remain inactive until the subscriber answers.

Having thus stated very briefly the direct operation of the cord and line-circuits, I will return to the trunk. The sleeve side of the trunk-jack J is provided witlithe choke-coil 4.- in order to furnish a path to ground similar to that through the cut-01f relay N of a subscribers line-circuit. This is necessary in Order that the relay B should supply cur: .rent for the supervisory lamp L. Except for the foregoing, the peculiar and characteristic features of my trunk-circuit are all located at the B end, or in the.B ofiice. The trunk-wires 12 pass respectively to the windings 2', i of the repeating coil, and

thence to the two sides of the condenser C. The twin windings 2' 2' of the repeating coil are connected interniediately to the opposite sides of condenser C, and at their outer ends to the extension wires 9, 10, whichlead to the trunk plug P through suitable flexible conductors.

Bridged across the' terminals of the condenser C is a relay R of very high resistance, which may be 15,000 ohms. I provide a shunt 11, 12, '13 about the relay R normally open at contacts 14, 95 of the relay R and containing a relatively low resistance relay R, whose windings may well be of 100 ohms resistance. The relay R .is the tip relay of the trunk, which corresponds to the tip relay R of the A operators cord- .circuit. Similarly, the relay R" is the sleeve relay of the trunk and corresponds to the sleeve relay R of the A operators cordcircuit. These two relays R R are connected across the trunk-conductors 9-1O by means of the wires 15, 16, 17, 18, with the mainbattery B connected between them.

This battery therefore supplies current through the contacts of the trunk-plug to the called subsoribers line, in the same manner that the battery B in the A operators cord-circuit. When a trunk-plug 'P is inserted in any line-jack J, the relay R will be at once energized by current flow through the following circuit: ground, 16, B, 17, Rt,

10, 7 J, N, ground and back to battery. The relay R when energized completes the normally open tip side 9 by closing the con-- tact 19, 20. At. the same time, it cuts off the operators test set 0, by opening the contacts 19 and 21. The latter contact is connected by wire 22through coil I.to ground. This thus be perceived that as long as the plug P is idle the tip side of the trunk is open and the tip of the plug P connected to the test set. Two other relays are provided, marked and R p ,The latter is controlled by. the

relay 3?, and itself controls the guard and disconnect lamp L. The former is under the control of the relay R and itself controls the ringing lamp L The operation'of these relays and the lamps will be clear from the general statement of operation hereinafter. The'relay R also .controls-theringing circuit, responding to the act of the A operator, in the following manner:- \Vhen the re lay R is energizedyit closes the following circuit: from battery B by wire 17, 23, R, 24, r and ground backto battery by wire 16. This energizes relay It, as already stated, which pulls up both its armatures r and r. The former closes the following circuit: p, 9, 26, r, 27, to the ringing keys, thence to the generator, and ground. The continuity of the ringing circuit from the generator to the plug tip is thus determined by the presence of the A operators callingplug P in the trunk-jack J, while the continuity of the tip side of the trunk 9, at its incoming or B end, is determined by the presence of the trunk-plug 1 in the jack J of the called line. Anotherpoint should be noted in pass ing,'viz., that the low resistance relay B", when energized, maintains the circuit of relay lt closed through the branch 28, T 29. That is to say either of the relays R or R will close the circuit of relay R, and the reason for this is apparent when it is considered-that the low relay R" shunts the high relay It, so that the latter becomes .dei nergized when the called subscriber answers. The purpose of having two relays R and Rfarranged as they are, is that the called-subscriber may control the supervisory lamp L in the A operators cord-circuit. The relay R by reason of its high resistance, will not pass sufficient current to effectively energize the tip relay R of the A operator (this relay usually having a resi ;tance of about 100 ohms),-but when the relay R is cut in across'the terminals of rela R sufficient current will immediately pass from the A operators battery B through the cord conductors 5-43, the trunkwires 12, coils 2', i, a" circuit 11, 12, 13, It,

' to energize the relay R in the cord-circuit,

.so that the lamp L which has. previously been burning will become extinguished and will thereby indicate to the A operator that the called subscriber has answered. The relay B it will be observed responds directly to the act of the called subscriber, becoming energized only when he takes down his receiver T and closes the circuit at the hook H.

The ringing key K is set by the B operator who continues to ring at the proper intervals as long as the ringing lamp continues to burn. This lamp L is normally connected to the front contact 30 of the relay It, and thence to battery through the wire 31, this connection being by way of the following circuit: 32, 7' 33, 30, 9- 31, 17, B, 16 and ground back to the lamp. \Vhen the sleeve relay R becomes energized upon the insertion of the plug P, therefore, the lamp will light. It can be extinguished only by the energization of relay R, which depends upon the energization of relay R when the called subscriber answers. R locks itself, however, after being once energized, and remains locked until the trunk plug is finally removed from the subscribers line-jack.

The energizing circuit is as follows: E, 17, 31,

1' 30, 33, 34;, 1- 35, R and ground back to battery by wire 16. The locking circuit is as follows: E, 17, 31, 9' 30, 33,7 36, 35, R and ground back to battery by wire 16. This locking circuit is of course broken at the contact 30 when the plug P is finally pulled out. of the jack. The lamp L is thus lighted only from the time the plugis inserted until the called subscriber answers, confusion of signals being thus avoided. The lamp L is first lighted when the A operators plug is inserted in the jack J, this being brought about by the energizaticn of the relays It and R in sequence. The lamp circuit is then as follows: 11), B, 17, 31, r", 37, W", L and ground back to battery. As soon as the plug 1 is inserted in the wanted line-jack, the relay It pulls up and breaks this circuit by separating the armature r from its back contact. The lamp then goes out, and it should be observed that if the B operator follows the proper sequence of steps, she will not attem )t' to insert the plug 1 or ring until this lamp lights. 'When the subscriber, having answered, finally hangs up-his receiver and thereby breaks his line-circuit, the relay R will become denergized and when the A operator pulls the plug P from the jack J, a relay R thereby becomes deenergized, the lamp L will again light,

upon the following circuit: 16, B, 17, 31,

ously. This is normal for the lamp L,

. sure of the circuit: B, 31, 33, 34, 38, etc.,

. formlng terminals for the trunk conductorsas last traced. The lighting of both lamps simultaneously serves as a guard signal to the operator that she is not yet to ring. Since the A operator has inserted the plug P in the trunk-jack the relays R and R will become energized, and the lamp L will become extinguished, while the lamp L will continue to burn, thereby advising the B operator that she may proceed to ring. Should she proceed previously, however, in

defiance of the guard signal, her manipula-.

tion of the key K will be idle, since the ringing circuit remains open at the contacts of the armature 1' controlled by the relay R. Thus in case of a mistake, or for any other reason, the A operator may prevent the B ing current on the wanted line.

-I have shown at K a four-party selective ringing .key. This has two master key sprlngs is, playing against anvil contacts 91 0, so that when these springs are open the continuity of the, trunk is interrupted in the usual manner for secondary ringing. I

also shdw four selective keys 70, if, if, is", each of which when actuated connects one of the selective generators G, G G or G to the wire 27, and thence through wire 26 to the tip of the plug p. The sleeve of the plug is connected through wire 10, and a master key spring is, when the key is in use,

through the resistance w and wire 39 to the battery and ground. The purpose of this is to supply the battery current to the cutofi relay N of the'line while ringing. The

spring k and the wire 10 may however be grounded directwithout going to the battery, if desired, without altering the invention. This arrangement of manual ringing is illustrated herein as a matter of convenience only. I contemplate practising my in vention with automatic ringing of any sort,

the characteristic feature of the invention.

being that the'ringing is' absolutely controlled by the A operator. Thus, the key K may be fitted with any desired form of latch, to be tripped when the called-sub scriber answers. Sucha latch is shown for exam l e, in Letters Patent No. 634,575, issued to Edwin W. Ham, October 10, 1899. Other methods of automatic ringing are very well known to those skilled in the art, and can be substituted for the method herein. illustrated without the slightest invention. It is unnecessary to illustrate t em therefore, and it will be understood th t I include them within the scope of my present claims.

I will now state briefly the following operation of effecting connection from the A operator from sending out ringoperators position after answering a call, through the mechanism and circuits shown in Fig. 1 to the subscribers station A. We will assume the calling subscriber to have been answered by the A operator, her answering plug, which forms the terminal of her conductors 40, 41 having been inserted in the calling line-jack, and the number wanted ascertained. We will assume that this number is of a station A connected to a difi'erent central oifice B. It thereforebecomes necessary for the A operator to trunk the connection. She then'proceeds as follows: Depressing an order button, she connects her telephone to an order circuit leading from the A to the B switchboards. This order circuit is not shown in the drawings, but being common and perfectly well known to all engineers, its illustration is thought unnecessary. The B operator is alreadyon the order circuit,'or

if desired she may have a signal for each circuit, and come in on the one calling. The A operator then communicates to'her the number of the line wanted, and in turn'the B operator designates the trunk to be used. 7e will assume this to be the trunk as shown in the Fig. 1. The A operator inserts plug P in the jack J, current flows from battery B through the trunk-condue tors 1-2 and the relay R this relay energizes the relay R and the lamp L lights before the B operator. The B operator at this time takes up the plug P and tests the multiple-jack of the line wanted, b touching the tip of the plug to the thimble of the jack J. if the plug is already in another multiple-jack of this line, the potential of this thimble will be raised through the following circuit from the battery: B, 17, R", 18, 10, -In this case the testing operator will receive a click, through thefollowing circuit: p, 9, 19, 21, 22, I and ground (secondary), 43, primary to the receiver O. The line will then be reported busy either by word of mouth, or by the. B operator inserting the plug P in a busy jack connected to a suitable tone producing device. Assuming the line wanted to be idle, the operator receiving no click inserts the plug P in the jack J, and thereby connects the trunk extension 9-10 to the line-wires 7--8. The rela Ii" im-. mediately pulls up, the lamp L up edia'tely goes out, and the lamp L immediately lights. The B o erator now manipulates the ringing key, an continues to "do so at intervals until the lamp L is extinguished, which occurs when the called subscriber answers, his line-circuit then being closed, and current flowing to the relay R over the following path: B, 17, R", 18, 10, 8, H, T,

T, 7, 9, 15, R, 16. The relay R immediately pulls up and locks itself, so that the lamp is locked out. The relay R*'-also pulls up, due to the closure of circuit 11, 1:3, 13, 14', 95, the relay R becomes deenergized, and effective current reaches the A operators relay R through the following circuit: 13:, R, 6, 2, i, R*, 13, 14, 95, 12, '2', 1, 5, R. Relay R thereupon pulls up and extinguishes the A operators supervisory lamp L, informing her that the called subscriber has answered. When the subscribers have finished their conversation, and hang up their receivers, they thereby sever their linecircuits, the answering supervisory signal of the A operator lights as usual, and the calling supervisory lamp L also lights, ow-

ing to the following operations in the trunk:

. The breaking of the called line-circui t 7- 0 at the switch H, causes the relay ll- 'to be-- come denergized. The circuit 11, 19., 13, 14, 95 is thereupon broken, and the relay It" is replaced in the shunt around the condenser C by the relay R, the etlect of this being the same upon the'supervism'y relay R as if the circuit had been broken. The

.A operator therefore gets the clearing-out signal. It will be observed, however, that the relay R maintains the circuit 28, 24, 23, etc., of the relay R in a closed condition. The Al -operator now pulls down her plugs.

, The removal of the plug P from the trunkjack J results in the cleenergization of the relay R which breaks the circuit of the relay R, and that in turn closes the circuit of the lamp L as follows: 16,13, 17, 31, r, 33, 34:, W, 38, 1*, L and ground back to baltery. This is the clearing-out signal for the: B operator, and she immediately pulls out the plug 1, whereupon the relay R loses current, and becoming deenergized breaks the circuit of the lamp -L" at the contact 30, and at the same point cuts oil the locking current from the relay R 'The lamp L thereupon becomes dark, and all the parts are restored to normal condition ready for another operation I claim and desire to secure by Letters Patent is 1. In a telephone exchange system, the combination of-a central exchange, a cord circuit at the exchange, a sub-exchange, a trunk circuit connecting the central exchange with the subexchange, a supervisory relay for the cord circuit, a high resistance relay in the trunk circuit connected in circuit with the supervisory relay upon connecthnrof the cord circuit with the trunk circuit, said highresistance relay preventing operation of the supervisory relay, a telephone line leading rpm the subexchange and terminating in substations, ringing mechanisms at the subcxrhaugc, automatic relay mechanism for controlling the connection of the ringing mechanism with the trunk circuit and telephone line connected therewith, a low resistance relay, and a controlling relay automaticallyoperated upon the response of the called subscriber for closing thecircuit of the low resistance relay, said high resistance relay being normally eii'ective to control the circuit for the automatic ringing relay, and said low resistance relay being connected in shunt of the high resistance relay upon operation of the controlling relay .to destroy the control of the automatic relay by the high"resistance relay and to assume the control of said automatic relay circuit.

2. In a telephone exchange system, the combination of a main vexchan e, a cord circuit at the main exchange, a su exchange, a trunk circuit forconnecting the main ex change with the subexchange, a telephone line leading from the subexchange and terminating in substations, a supervisoryre 'lay for the cord circuit, a high resistance and alow resistance relay for the trunk circuit, a controlling relay for. controlling the circuit of the low resistance relay, connection of the cord circuit with the trunk circuit causing closure of a circuit including the super visory relay and the high resistance relay. said high resistance relay preventing operation of the supervisory connection of. the trunk circuit with the telephone line and operation of telephone apparatus at the connected substation causing closure of a circuit through the controlling relay whereby the low resistance relay is bridged'about the.

high resistance relay and the supervisory relay rendered operative, ringing mechanism associated with the trunk circuit, automatic relay mechanism for controlling the connection of the ringing mechanism with the trunk circuit, said automatic ring-i ing mechanism circuit-being first controlled by the high resistance relay and their by the low resistance relay.

3. In a telephone exchange system, the combination of a cord circuit, a trunk 'cir' cuit, normally closed master key springs in said trunk, aringing circuit, extending through a normally open operators key and normally open also at a second point independent of said master key springs, and relay mechanism for closing the ringing circuit at such second point, such relay mechanism being controlled by the connection of the cord circuit with the trunk circuit.

1. In a telephone system, the combination of a central exchange, connectin conductors thereat, a subexchange, a trun circuit for connecting the central exchange with the suhexchange, a telephone line leading from the subexchange and terminating ata substation, a source of ringing current at the I subexchange in a circuit normally disccnnected from the trunk circuit, an operators key at the subexchange, relay mechanism under the control ofthe central exchange operator for placing the ringing circuit under the control of such operators key, said ringing circuit being completed through to said key when said. sub and central exchanges are connected and a source of current connected to said central exchange connecting conductors for controlling said re lay mechanism.

5. In a telephone exchange system, the

combination of a central exchange, a sub ringing circuit by such operators key, said means being controlled by said source and when operated completing the ringing cir-- cuit through to the operators key.

6.. In a telephone exchange system, a central exchange, a subexchange, a trunk connecting the exchanges, a source of ringing current at the subexchange normally disconnected frcm the trunk, a master key in said trunk, a circuit for said ringing cur rent independent of said master key and normally interrupted at two points, and means cont-rolling one of the interruptions under the influence of the central operator.

7. In a central telephone system. a central exchange, a s u'ce of current thereat, a cord circuit thereat, a subexchange, a trunk circuit between said two exchanges, switch means for connecting the cord and trunk circuits, a subscribers line terminating at each exchange, a source of ringing current at the subexchange normally disconnected from said trunk circuit, a relay controlliingthe connection of said source to said trunk. and operated by-current from said central exchange source, a circuit for said relay closed as long as said cord circuit is connected to said trunk. i

1 8. In a central telephone system, a central exchange, a cord circuit thereat, a source of current thereat, a subexchange, a trunkcircuit connecting the said two exchan es, means for connecting the cord an trunk circuits, subscribers lines terminating at each exchange and adapted to be connected bythe cord and trunk circuits, a source of signaling current normally disconnected from the connecting circuits, a circuit for said signaling source, a relay controll' 0 said circuit, a circuit for said relay incliiiIing the central exchange current source, means in the trunk for controlling said relay circuit, saidlast named means operated to control said circuit as lon as the cord circuit is connected to the trun circuit.

9. In a telephone exchange system, a central exchange, a cord circuit thereat, a sa pervisory relay thereat, a subexchange, a trunk circuit connecting said subexchange and said central exchange, a source of signa-ling current normally disconnecting from subexchange, a telephone line leading tram circuit controlling both the signaling current and the supervisory relay.

10. In a telephone exchange system, a main exchange, a cord circuit, a s'ubexchange, a trunk circuit adapted to be connccted to the cord circuit, subscribers lines adapted to be interconnected by said cordand trunk circuits, a source of signaling current, a circuit for said signaling source normally interrupted to disconnect said signaling source from said main circuit, and operators ringing key in said circuit; a supervisory relay, a relayinsaid trunk circuit controlling said relay, and said circuit for said signaling source, said controlling relay adapted, when operated, to connect said ringing circuit through to the operators In testimony whereof I atfix my signature in presence of two witnesses.

RAY H. MANSON. lVitnesses:

A. J. ROBERTS, WM. G. STRONG.

copies of this patent may heohtained for life cents each, by dressing the "Oontmtssionar a! intents.

' Washington, 29. 1 

